Device for measuring oxygen content in a gas medium
First Claim
1. Apparatus for measuring the oxygen content of a medium, the apparatus comprising:
- a sensor having a porous wall for communicating a volume thereof with said medium arranged for delivering a voltage representative of the ratio between a reference oxygen pressure and oxygen pressure in a fraction of said medium present in a volume of the sensor, and provided with electrodes enabling a pumping current to be passed for controlling said oxygen pressure in the volume; and
monitoring and control means including a digital controller connected to receive said representative voltage on an input thereof and arranged for delivering the pumping current;
the apparatus being characterized in that the monitoring and control means deliver pumping current in the form of a current that varies continuously and progressively, without interruptions, governed by the digital controller to servo-control said representative voltage and to maintain said representative voltage at a determined value.
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Accused Products
Abstract
The apparatus includes a sensor capable of delivering a voltage representative of the ratio between a reference oxygen pressure and the oxygen pressure in a volume of the sensor and provided with electrodes (12, 14) via which it is possible to pass a pumping current that controls said oxygen pressure in the volume, and monitoring and control means including a digital controller (26) receiving said representative voltage on an input and suitable for delivering the pumping current. The monitoring and control means deliver the pumping current in the form of a current that varies continuously and progressively, without interruptions, governed by the digital controller in such a manner as to servo-control the input voltage to a determined value.
17 Citations
11 Claims
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1. Apparatus for measuring the oxygen content of a medium, the apparatus comprising:
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a sensor having a porous wall for communicating a volume thereof with said medium arranged for delivering a voltage representative of the ratio between a reference oxygen pressure and oxygen pressure in a fraction of said medium present in a volume of the sensor, and provided with electrodes enabling a pumping current to be passed for controlling said oxygen pressure in the volume; and
monitoring and control means including a digital controller connected to receive said representative voltage on an input thereof and arranged for delivering the pumping current;
the apparatus being characterized in that the monitoring and control means deliver pumping current in the form of a current that varies continuously and progressively, without interruptions, governed by the digital controller to servo-control said representative voltage and to maintain said representative voltage at a determined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Apparatus for measuring an oxygen content in exhaust gas of an internal combustion engine, comprising:
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a sensor for delivering a voltage representative of a ratio between a reference oxygen pressure and oxygen pressure in a volume of the sensor, communicating with said exhaust gas by a porous wall provided with electrodes enabling a pumping current to be passed for pumping oxygen out of the volume and controlling said oxygen pressure in the volume; and
monitoring and control means including;
digital controller means connected to receive said representative voltage on an input thereof and arranged to deliver a time-modulated control voltage, and a series arrangement of a lowpass filter and a current generator connected to receive said time modulated control voltage and arranged for delivering said pumping current to said electrodes of the sensor in the form of a current having steady variations without time interruptions, said digital controller means being programmed to continuously adjust said time modulated control voltage for maintaining the representative voltage at a predetermined value, whereby said pumping current is a representation of said oxygen content. - View Dependent Claims (11)
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Specification